Why does Satan attack the nation of Israel?
Satan attacks the nation of Israel because he must thwart God's plan for the ages. Through Abraham's covenant, God promised the Messiah, the Redeemer of all mankind, would come. Satan must do anything in his power to stop that plan, and he has to start with Israel.
Les explains that God made a covenant with Abraham, promising that through his seed would come the Messiah, the Redeemer of all mankind. Because Satan must do anything in his power to somehow thwart God's plan for the ages, he constantly attacks the little nation of Israel. Les emphasizes that Satan has to start with the nation of Israel to try to stop God's plan, since Israel is the nation through which the Messiah would come. This is why Israel is the focus of Satan's attacks.
Who are Israelites; to whom pertaineth the adoption, and the glory, and the covenants, and the giving of the law, and the service of God, and the promises;